Growth Is Helping Costco at the Margins

Membership has its privileges. Just as with American Express cards, though, it is hard to say if Costco Wholesale Corp.'s 37.4 million members benefit from the privilege as much as the company does. The retailer saw no repercussions after it raised annual membership fees by a 10th in late 2011. Renewal rates remain around 90%.

Fiscal second-quarter results due Tuesday continue to reflect that increase due to deferred accounting. Costco already disclosed that same-store sales rose 6% for the quarter ended in February....